Question: What is a tributary of the Madeira River:
Paraphrase: What could be a tributary of the Madeira River:
SPARQL (Wikidata): SELECT ?answer WHERE { wd:Q118251 wdt:P403 ?X . ?X wdt:P974 ?answer}
Answer: Xingu River, Jurua River, Madeira River, Rio Negro, Japurá River, Ucayali River, Putumayo River, Preto da Eva River, Nanay River, Tapajós River, Napo River, Javary River, Paru River, Trombetas River, Jari River, Solimões, Jutai River, Urubu River, Jandiatuba River, Manacapuru River, Paraná Urariá, Uatumã River, Nhamundá River, Arabela River, Itaya, Guajará River